The present invention relates to a semiconductor memory device, and more particularly to a data output buffer of a semiconductor memory device. Along with the high integration and high speed of semiconductor memory devices comes the generation of noise in a chip, which causes malfunction thereof and lowers its reliability. There are many reasons for the generation of noise in a chip, but noise generated during data operation in a data output buffer is especially serious. The noise generated in data operations is due to the sudden and drastic change of data from low logic states to high logic states and vice versa.